Okay, where I am from there are quite a few guys who do the heating but don't know how to install an a/c. That's perfectly fine and so they hire me to hook em up and test em or repair ones they had installed recently that aren't working or never worked from the start.
I've been doing work for this particular contractor for about a year now and I've taken good care of him and his customers, but I guess I charge too much because recently he's hired a plumber to do some work for him. I've never messed anything up on his jobs so it's not a workmanship issue. I got a call from one of his friends' to repair their a/c unit. Upon arrival, the homeowner told me about the other tech who diagnosed the condenser fan motor. Well the capacitor was bulging and I tested it....of course this was the only proble. 45 and 3 microfarad by the way, try finding one of those...
Got another call on the same day to look at another a/c for this contractor. Apparently this other tech(the plumber) had diagnosed a "completely plugged suction line" AND it needed some sort of part. Well, I like to start from scratch and went to the condenser. I found the schrader valve stems removed, the service valves open. So the system had been open to atmosphere for a few weeks apparently. Good grief. Anyway, I replaced the drier, nitrogen, vacuum, charged to specs. High head pressure and low suction. hmmm.......Go inside and have a look at txv. Bulb was loose and un-insulated but that was minor in comparison to the fact it was an R22 coil on an R410a condenser system.
This ain't gonna be a cheap fix. A lot of billable hours.
I am not God's gift to the trade and I've made my mistakes in the past but come on now, let's not hire a plumber to repair an a/c system.